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Solid-State Lighting Science EFRC

Welcome to our SSLS EFRC

Sandia National Laboratories is home to one of the 46 multi-million dollar Energy Frontier Research Centers (EFRCs) funded by the U.S. Department of Energy Office of Science. These Centers integrate the talents and expertise of leading scientists in a setting designed: to accelerate basic and advanced discovery research; and to establish the scientific foundation for a fundamentally new U.S. energy economy that enhances U.S. energy security and protects the global environment in the century ahead.

Our own EFRC is focused on solid-state lighting science.  Solid-state lighting (SSL) is simply the use of solid-state devices, like light-emitting diodes, or like the lasers which are illuminating the frosted white post in the left graphic shown above, to produce white light for general illumination.  The goal of our SSLS EFRC is to help build the scientific foundation that enables solid-state lighting to produce the most light for the least energy, both in the U.S. and, as a side-benefit, throughout the world.

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A Brief History of Artificial Lighting Technology

As discussed in “Light Emitting Diodes (LEDs) for General Illumination, Update 2002, An OIDA Technology Roadmap” (co-sponsored by the U.S. Department of Energy, the National Electrical Manufacturers Association, and the Optoelectronic Industry Development Association), artificial lighting technologies are substitutes for sunlight in the 425-675 nm spectral region where sunlight is most concentrated and to which the human eye has evolved to be most sensitive.  The history of lighting can be viewed as the development of increasingly efficient technologies for creating visible light inside, but not wasted light outside, of that spectral region.

The three traditional technologies are Fire, Incandescence, Fluorescence; Solid-State Lighting constitutes a new, fourth technology.  These four technologies can be differentiated by the type of material (gas or solid) that emits the light, by the spectral bandwidth (broadband blackbody or narrowband) of the light emission, and by the fuel (chemical or electrical) used to create the light.  These differences, in turn, have consequences on the fundamental efficiencies of the technologies.

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A Brief History of Solid-State Lighting Technology

Semiconductor electroluminescence was first reported by H.J. Round in 1907, and the first light-emitting diode (LED) was reported by O.V. Losev in 1927.   Not until the birth of semiconductor physics in the 1940s and 1950s, however, was scientific development of technologies for light emission possible.

For solid-state lighting, the use of semiconductor electroluminescence to produce visible light for illumination, the seminal advances were: first, the demonstration of red light emission by N. Holonyak in 1962;  and, second, the demonstration of a bright blue LED by S. Nakamura in 1993,  along with earlier materials advances by I. Akasaki and H. Amano. Here, we briefly discuss these two advances and their subsequent evolution; more details can be found in “Light Emitting Diodes” and in “Solid-state lighting: ‘The case’ 10 years after and future prospects.”

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Solid-State Lighting Technology: Current State of the Art and Grand Challenges

The graphic on the left shows the anatomy of a state-of-the-art white solid-state lamp; and the graphic on the right shows in the black curve the spectral power density of the light that it emits.  The lamp is basically a blue LED coated with green and red phosphors.  Some of the blue light leaks through the phosphors, so you see this relatively narrower peak here in the blue part of the spectral power density.  But some of the blue light is absorbed by the phosphors and is re-emitted as green and red light, so you see these two relatively wider peaks here in the green and red parts of the spectral power density.  The combination of blue, green and red gives a white light that renders fairly faithfully colors of objects in the environment around us.

The efficiency of this state-of-the-art SSL lamp is about 20-25%, slightly better than that of a fluorescent lamp, but far from the 50-100% efficiency that is in principal possible. Why is this?  We can see why by looking at the three sub-efficiencies associated with the lamp.

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Our EFRC: helping advance the scientific foundation that enables major improvements in efficiency

The goal of our SSLS EFRC is not to work on advancing the technology itself; that is something that industry is extremely good at.  Our goal instead is to help advance the scientific foundation that underlies current and potential-future SSL technology so that all of these sub-efficiencies can be improved.  We do this through seven Scientific Research Challenges discussed in more detail elsewhere in this website.  Very briefly, these are:

These Scientific Research Challenges, again as discussed in more detail elsewhere in this website, have as common themes:

  • Researching the fundamental mechanisms that limit energy efficiency in the current generation of SSL technology
  • Exploring new, nanophotonic routes, such as nanowires, quantum dots, and lasers, to the conversion of electricity to light with the potential for much higher efficiencies.

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SSLS Contacts

Technical Inquiries
Mike Coltrin, Director
Sandia National Laboratories
P.O. Box 5800, MS 1086
Albuquerque, NM 87185
mecoltr@sandia.gov
(505) 844-7843
Jeff Tsao, Chief Scientist
Sandia National Laboratories
P.O. Box 5800, MS 1421
Albuquerque, NM 87185
jytsao@sandia.gov
(505) 844-7092
Jerry Simmons, Sr. Manager
Sandia National Laboratories
P.O. Box 5800, MS 1421
Albuquerque, NM 87185
jsimmon@sandia.gov
(505) 844-8402
Partnerships and Business Development Inquiries
Alyssa Christy
Sandia National Laboratories
P.O. Box 5800, MS 1421
Albuquerque, NM 87185
ajchris@sandia.gov
(505) 844-4542
Rene Sells
Sandia National Laboratories
P.O. Box 5800, MS 1421
Albuquerque, NM 87185
rmgonza@sandia.gov
(505) 844-2882
 
General Inquiries About Sandia: 

Please visit: http://www.sandia.gov/contact-us

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SSLS News

SSLS Scientist Andy Armstrong Receives 2013 Employee Recognition AwardCongratulations to SSLS EFRC Sr. Investigator Andy Armstrong, who was honored with Sandia’s 2013 Employee Recognition Award. Andy was awarded in recognition of his development and application of novel defect characterization for III-Nitride materials. Sandia’s prestigious Employee Recognition Awards (ERA) are presented to individual employees and teams nominated by their peers and chosen by a […]
Jerry Simmons Is One of Three Researchers Named as Laboratory FellowsThis status is reserved for those who are nationally or internationally recognized pioneers in their fields. It is considered a promotion to the highest level of R&D staff, equivalent to the level of management immediately below Sandia’s vice presidents. “The three new fellows have histories of sustained and equally distinguished accomplishments in their fields,” said […]
EFRC Scientist Weng Chow Awarded the Quantum Electronics AwardEFRC Sr. Investigator Weng Chow is the recipient of the 2013 Quantum Electronics Award. This highly prestigious award presented by the IEEE Photonics Society is given to a select group of scientists who are considered pioneers in the field of quantum electronics. Chow is receiving this award on behalf of his, “contributions to semiconductor-laser theory, […]
Sandia Develops a Synthesis of Quantum Dots that Increases the Quantum Yield to 95.5%White light-emitting diodes (LEDs) based on blue indium-gallium-nitride (InGaN) LEDs that excite yellow-green-emitting yttrium-aluminum-garnet: cerium phosphors (YAG:Ce, a nonhygroscopic, chemically inert inorganic scintillator) have a cold white emission that can be made warmer with the addition of a red-emitting component. Unfortunately, red emitters that satisfy all criteria for use in solid-state lighting (SSL) applications are […]
Sandia’s Dr. Jeffrey Tsao Is Recognized as an Asian-American Engineer of the YearDr. Tsao, a Distinguished Member of Sandia’s Technical Staff in the Semiconductor and Optical Sciences Department, is one of eight distinguished engineers upon whom this award was conferred this year by the AAEOY organization. He received this honor for, “sustained contributions to compound semiconductor materials and device science and exemplary contributions to solid-state lighting technology.” […]

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SSLS Publications

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